1. Field of the Invention
The present invention relates mainly to a fastening fixture suited for fixing a cable running member on a channel rail.
2. Related Art
In the cable running work, there is indispensable a work to fix a cable running member, as represented by a beam member for forming a race way or duct, on a channel rail.
As the fastening fixture for this purpose, there have been made in the prior art a variety of proposals including the fixing of cable conduits, as disclosed in U.S. Pat. No. 4,770,378. According to this disclosure, a plate nut is screwed on a bolt having the seat for the fixture body.
However, this fastening fixture of the prior art is operationally troublesome because the plate nut has to be adjusted before use to a predetermined direction (to have its longitudinal direction in parallel with the rail channel). On the other hand, the direction of the plate nut is accidentally changed by a vibration or by contact with foreign obstacle. After the plate nut was inserted into the channel of the rail, moreover, the bolt head has to be operated each time to turn the plate nut by 90 degrees to cross the channel rail. If the bolt is then erroneously turned to a looser side, the plate nut comes out from the bolt and falls into the channel rail. As a result, working mistakes frequently occur to raise a problem that the work of this kind to fasten and fix a number of targets takes a long time to lower the efficiency.
Moreover, it is essential for the fastening fixture of the prior art to regulate the turn of the plate nut by bringing the two longitudinal ends of the plate nut into abutment against the inner flange walls of the channel rail. Therefore, the plate nut is enlarged in its size, especially in its length so that it is easily warped if subjected to the strong fastening force of the bolt. In order to prevent this warpage, it is necessary to increase the thickness of the plate nut. As a result, there arises a problem that the entire fastening fixture is large-sized and heavy so that it is difficult to handle when transported or worked.
Because of the type in which the two longitudinal ends of the plate nut are brought into abutment against the inner flange walls of the channel rail, on the other hand, the plate nut cannot be applied to a channel rail having a different inner width. Many kinds of plate nuts have to be uneconomically prepared for the kinds of the inner width of the channel rail. Another problem is that the plate nut cannot be used for a structure (of a hole type) which has no wall on the two inner sides other than the channel rail.
Since the turn is stopped by bringing the two longitudinal ends of the plate nut into the inner flange walls of the channel rail, moreover, serious affects are exerted on the surface characteristics of the inner flange walls of the channel rail. If the inner flange walls of the channel rail are made coarse or corrugated, more specifically, the plate nut does not cross the longitudinal direction of the rail channel at a right angle but is caught obliquely so that the screw cannot be turned or so that the plate nut lifts at the oblique position, as viewed in a top plan view. As a result, the plate nut is fastened without retaining a sufficient fastening area between itself and the entrance channel walls of the channel rail, so that the fastened state is liable to become unstable or unreliable to have a poor reliability in the fixing performance.
The invention has been conceived to solve the problems of the prior art and has an object to provide a fastening fixture which is enabled to fix a target temporarily and to fasten and fix the same by an remarkably simple operation, independently of the depth of the rail channel and the size of the inner flange size and which has a simple and small-sized structure and requires a small number of parts so that it can be manufactured at a low cost.
Another object of the invention is to provide a fastening fixture which can be applied not only to the channel rail but also to a holed member having no inside wall.
In order to achieve the above-specified objects of the invention, according to the invention, there is provided a fastening fixture comprising: a fixture body for fixing a target on a channel rail or a holed member; a screw having its stem portion inserted into the fixture body; and a fastening nut having an internally threaded hole to be screwed on the stem portion of the screw, wherein the fixture body includes a depending member extending in parallel with the stem portion of the screw, and wherein the fastening nut includes a guide portion to be fitted on the depending member, at the central portion of its longer side edge portion, whereby the turn of the fastening nut is regulated by the depending member and the guide portion so that it is allowed to move only in parallel with the stem portion of the screw.
Since the fastening nut is not changed in its direction relative to the fixture body by the relation between the depending member and the guide portion, according to the construction, the longer side of the fastening nut is automatically brought into parallel with the entrance channel if the fixture body is gripped by the hand and directed to cross the channel rail entrance channel or the entrance of the hole of the holed member, so that the fastening nut is inserted into the inside of the channel rail through the entrance channel or the entrance of the hole. If the fixture body is turned clockwise or counter-clockwise by 90 degrees while being gripped, the longer side of the fastening nut is oriented below the entrance walls forming the entrance channel or hole and perpendicularly of the entrance walls. By hooking the essential portion of the fixture body to bring the same into engagement or contact with the target, therefore, the temporarily fixed state can be established. If the screw is then turned, the fastening nut is lifted along the depending member while its lower side holding the relation to cross the entrance walls or hole at a right angle, and its upper face abuts strongly against the lower faces of the entrance walls so that it is firmly fastened and fixed by the fixture body. Therefore, the target can be fixed simply and promptly on the various channel rails or holed members having no side wall.
Preferably, the fastening nut has a shorter side of a width smaller than the width of the entrance channel of the channel rail and a longer side of a length larger than the width of the entrance channel but smaller than the inner width of the channel rail. Therefore, the fastening nut can be made compact, and the channel rail can be coped, now matter how large its inner width might be, with the fastening fixture of one kind.
The guide portion could take a variety of modes. In one mode, the guide portion includes a projection having a T-shape, as seen in a top plan view, and has a projection extending outward from the longer side edge portion and extensions extending to the two sides from the leading end of the projection. In this case, the depending member of the fixture body includes a longitudinal groove having a width corresponding to the projection. In another preferred mode, the guide portion has a hole. This hole has not only a closed contour but also a partial groove leading to the outside. In this case, the depending member is made of a bar to extending through the hole. Where the guide portion has the hole structure, the depending member does not come out in the least, so that it can ensure both the two turn-stopping and guiding actions.
The fastening nut is basically composed of a single part. The fastening nut is formed of not only a flat plate but also a channel-shaped section including rising walls at its longer side edge portion or its shorter side edge portion. With these rising walls, the fastening nut is enhanced in strength by the angle effect so that it can effect the strong fixing even if it is made thin.
On the other hand, an elastic member is preferably interposed between the lower face of the fixture body and the fastening nut for urging the fastening nut away from the fixture body. Before the proper fastening and fixing, according to this structure, the fastening nut can be held without shaking at a predetermined spacing from the fixture body. At the fastening and fixing time, moreover, the head of the screw does not float so that the screw can be smoothly turned. After the fastening nut was fastened, still moreover, the pushing force of the elastic member acts on the fastening nut so that the screw is not loosened even with any vibration.
Preferably, the stem portion of the screw includes a stopper portion at its lower end. This stopper portion exhibits not only the function to prevent the fastening nut from coming out but also the function to set the set position (or the lower limit) of the fastening nut in association with the elastic member.
In order to regulate the turn of the fastening nut and to allow only the parallel movement in parallel with the stem portion of the screw, according to the invention, the fixture body includes a relatively wide depending member to confront the lower side of the fastening nut. In this case, the fastening nut need not be equipped with any special guide portion so that the structure can be more simplified and small-sized to lower the cost.
The fixture body of the invention should not be limited to a single part having the depending member formed integrally with itself.
The fixture body includes a first portion having a seat portion to be seated on the channel rail, and a second portion to be combined with the first portion, and the second portion has a portion (or a body portion) to contact with the seat portion of the first portion and a depending member bent down to extend at a right angle from the leading end of the body portion.
In the invention, the name xe2x80x9ctarget to be fixedxe2x80x9d conceptionally covers the various members of various shapes and structures in the cable running work, such as beam materials, e.g., master beams or slave beams, partitions, outlet boxes or separators. On the other hand, therefore, the fixture body of the invention has various shapes and structures according to that target. In any case, however, the fixture body has a portion for engaging with, hooking, biting or jointing the target such as the essential portion (or the holding portion) for fixing the target on the channel rail or the holed member.
Although the remaining features and advantages of the invention will become apparent from the following detailed description, the invention should not be limited to the constructions exemplified by embodiments so long as the constructions are provided with the fundamental features of the invention, but could be apparently modified or corrected in various manners by those skilled in the art, without departing from the scope of the invention.